Light emitting device and light emitting device package

ABSTRACT

A light emitting device according to the embodiment includes a first electrode; a light emitting structure including a first semiconductor layer, an active layer and a second semiconductor layer on the first electrode; a second electrode on the light emitting structure; and a control switch installed on the light emitting structure to control the light emitting structure.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a Continuation of co-pending U.S. applicationSer. No. 13/033,224 filed on Feb. 23, 2011, which claims priority under35 U.S.C. 119(a) to Korean Patent Application No. 10-2010-0033835 filedon Apr. 13, 2010, whose entire disclosures are hereby incorporated byreference.

BACKGROUND

The embodiment relates to a light emitting device and a light emittingdevice package.

A light emitting diode (LED) is a semiconductor light emitting devicethat converts current into light. The LED can generate light having highbrightness, so that the LED has been expensively used as a light sourcefor a display device, a vehicle, or a lighting device. In addition, theLED can represent a white color having superior light efficiency byluminescence materials or combining LEDs having various colors.

SUMMARY

The embodiment provides a light emitting device having a novel structureand a light emitting device package.

The embodiment provides a light emitting device having a switchfunction.

According to the embodiment, the light emitting device may include afirst electrode, a light emitting structure including a firstsemiconductor layer, an active layer and a second semiconductor layer onthe first electrode, a second electrode on the light emitting structure,and a control switch on the light emitting structure to control thelight emitting structure.

According to the embodiment, the light emitting device may include afirst electrode, a light emitting structure including a firstsemiconductor layer on the first electrode, an active layer on the firstsemiconductor layer and a second semiconductor layer on the activelayer, a second electrode on the second semiconductor layer, a body onthe second semiconductor layer, source and drain regions on the body, agate insulating layer on the body between the source and drain regions,and a gate electrode on the gate insulating layer, wherein the secondelectrode is electrically connected to one of the source region and thedrain region.

According to the embodiment, the light emitting device package mayinclude a package body, a light emitting device on the package body, anda molding member surrounding the light emitting device, wherein thelight emitting device includes a first electrode, a light emittingstructure including a first semiconductor layer, an active layer and asecond semiconductor layer on the first electrode, a second electrode onthe light emitting structure, and a control switch on the light emittingstructure to control the light emitting structure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of a light emitting device according to thefirst embodiment;

FIG. 2 is a plan view of a light emitting device;

FIG. 3 is a circuit view showing an operational principle of a lightemitting device of FIG. 1;

FIGS. 4 to 12 are sectional views showing a method of manufacturing thelight emitting device according to the first embodiment;

FIG. 13 is a sectional view of a light emitting device according to thesecond embodiment;

FIG. 14 is a sectional view showing a light emitting device packageincluding a light emitting device according to the embodiment;

FIG. 15 is an electrode perspective view showing a display deviceaccording to the embodiment;

FIG. 16 is a sectional view showing a display device according toanother embodiment; and

FIG. 17 is a perspective view showing a lighting device according to theembodiment.

DETAILED DESCRIPTION OF THE EMBODIMENTS

In the description of the embodiments, it will be understood that, whena layer (or film), a region, a pattern, or a structure is referred to asbeing “on” or “under” another substrate, another layer (or film),another region, another pad, or another pattern, it can be “directly” or“indirectly” over the other substrate, layer (or film), region, pad, orpattern, or one or more intervening layers may also be present. Such aposition of the layer has been described with reference to the drawings.

The thickness and size of each layer shown in the drawings may beexaggerated, omitted or schematically drawn for the purpose ofconvenience or clarity. In addition, the size of elements does notutterly reflect an actual size.

FIG. 1 is a sectional view of a light emitting device according to thefirst embodiment, and FIG. 2 is a plan view of the light emittingdevice.

Referring to FIGS. 1 and 2, the light emitting device 100 according tothe embodiment includes a first electrode 160, an adhesive layer 158 onthe first electrode 160, a protective member 155 on the first electrode160 or on an outer peripheral region of a top surface of the adhesivelayer 158, a reflective layer 157 on the adhesive layer 158, an ohmiccontact layer 156 on the reflective layer 157, a light emittingstructure 145 on the protective member 155 and the ohmic contact layer156, a second electrode 170 on the light emitting structure 145, and acontrol switch 120.

The first electrode 160 supports a plurality of layers formed thereonand has a function of an electrode. In detail, the first electrode 160may include a support member having conductivity. The first electrode160, together with the second electrode 170, supplies power to the lightemitting structure 145.

For instance, the first electrode 160 may include at least one of Ti,Cr, Ni, Al, Pt, Au, W, Cu, Mo, Cu—W and a carrier wafer including Si,Ge, GaAs, ZnO, SiC, SiGe, or GaN.

The first electrode 160 can be plated and/or deposited below the lightemitting structure 145 or can be attached in the form of a sheet, butthe embodiment is not limited thereto.

The adhesive layer 158 may be formed on the first electrode 160. Theadhesive layer 158 is a bonding layer formed under the reflective layer157. Outer side surfaces of the adhesive layer 158 are exposed and theadhesive layer 158 makes contact with the reflective layer 157 to serveas a mediator for reinforcing the bonding strength between the firstelectrode 160 and the reflective layer 157.

The adhesive layer 158 may include a barrier metal or a bonding metal.For instance, the adhesive layer 158 may include at least one selectedfrom the group consisting of Ti, Au, Sn, Ni, Cr, Ga, In, Bi, Cu, Ag andTa.

If the first electrode 160 is formed through the plating scheme or thedeposition scheme, other than the bonding scheme, the adhesive layer 158may be omitted.

The protective member 155 is formed on the outer peripheral region ofthe top surface of the reflective layer 157. In detail, the protectivemember 155 is formed at the outer peripheral region among the lightemitting structure 145, the ohmic contact and the adhesive layer 170.

The protective member 155 may include a material having electricinsulating property or electric conductivity lower than that of thelight emitting structure 145. For instance, the protective member 155may include at least one selected from the group consisting of Si02,SixOy, Si3N4, SixNy, SiOxNy, Al2O3 and TiO2. In this case, theprotective member 155 may prevent the electric short from occurringbetween the light emitting structure 145 and the first electrode 160,thereby improving the reliability of the light emitting device 100.

The protective member 155 may include a metal having superior adhesiveproperty. For instance, the protective member 155 may include at leastone selected from the group consisting of Ti, Ni, Pt, Pd, Rh, Ir and W.In this case, the protective member 155 may reinforce the adhesivestrength between the light emitting structure 145 and the reflectivelayer 157, so that the reliability of the light emitting device 100 canbe improved. In addition, the protective member 155 may not be broken orfragments of the protective member 155 may not be generated when thelaser scribing process or the laser lift off (LLO) process is performedto break a plurality of chips into individual chip units, so that thereliability of the light emitting device 100 can be improved. Inaddition, if the protective member 155 makes ohmic-contact with thefirst conductive semiconductor layer 150, the current may flow throughthe protective member 155. In this case, the active layer 140, whichoverlaps on the protective member 155 in the vertical direction, cangenerate the light, so that the light emitting efficiency of the lightemitting device 100 may be further improved. For instance, if the firstconductive semiconductor layer 150 is a p type semiconductor layer, theprotective member 155 may include a metallic material, such as Ti, Ni orW, capable of forming the ohmic contact with respect to the p typesemiconductor layer, but the embodiment is not limited thereto.

The protective member 155 may be formed on the outer peripheral regionof the top surface of the adhesive layer 158. The protective member 155prevents the electric short between the light emitting structure 145 andthe first electrode.

The protective member 155 may include a material having electricinsulating property. For instance, the protective member 155 may includeat least one selected from the group consisting of SiO₂, Si_(x)O_(y),Si₃N₄, Si_(x)N_(y), SiO_(x)N_(y), Al₂O₃, TiO₂, ITO, AZO, and ZnO.

The reflective layer 157 may be formed on the adhesive layer 158. Thereflective layer 157 reflects light incident from the light emittingstructure 145, thereby improving the light extraction efficiency of thelight emitting device 100.

The reflective layer 157 may include a material having superiorreflective property. For instance, the reflective layer 157 may includea metal or an alloy including at least one of Ag, Al, Pt, Pd and Cu.

For instance, the reflective layer 157 may include a metal or a metalalloy including at least one selected from the group consisting of Ag,Ni, Al, Rh, Pd, Ir, Ru, Mg, Zn, Pt, Au, and Hf, but the embodiment isnot limited thereto. In addition, the reflective layer 157 can beprepared as a multi-layer by using the above metal and transparentconductive materials including one selected from the group consisting ofIZO (In—ZnO), GZO (Ga—ZnO), AZO (Al—ZnO), AGZO (Al—Ga—ZnO), IGZO(In—Ga—ZnO), IZTO (indium zinc tin oxide), IAZO (indium aluminum zincoxide), IGTO (indium gallium tin oxide) and ATO (aluminum tin oxide).For example, the reflective layer 157 has the multi-layer structureincluding one of IZO/Ni, AZO/Ag, IZO/Ag/Ni and AZO/Ag/Ni.

The ohmic contact layer 156 may be formed on the reflective layer 157.The ohmic contact layer 156 makes ohmic-contact with the firstconductive semiconductor layer 150 of the light emitting structure 145to easily supply power to the light emitting structure 145.

In detail, the ohmic contact layer 156 selectively includes thetransparent conductive material and the metal. For instance, the ohmiccontact layer 156 can be prepared as a single layer or a multiple layerby using at least one selected from the group consisting of ITO (indiumtin oxide), IZO (indium zinc oxide), IZTO (indium zinc tin oxide), IAZO(indium aluminum zinc oxide), IGZO (indium gallium zinc oxide), IGTO(indium gallium tin oxide), AZO (aluminum zinc oxide), ATO (antimony tinoxide), GZO (gallium zinc oxide), IrOx, RuOx, RuOx/ITO, Ni, Ag,Ni/IrOx/Au and Ni/IrOx/Au/ITO.

If the reflective layer 157 makes ohmic-contact with the light emittingstructure 145, the ohmic layer 156 may be omitted.

The light emitting structure 145 may be formed on the ohmic contactlayer 156 and the protective member 155. The light emitting structure145 may include a plurality of group III-V compound semiconductormaterials.

The light emitting structure 145 may include the first conductivesemiconductor layer 150, the active layer 140 on the first conductivesemiconductor layer 150, and the second conductive semiconductor layer130 on the active layer 140.

The first conductive semiconductor layer 150 can be formed on a portionof the protective member 155 and on the ohmic contact layer 156. Thefirst conductive semiconductor layer 150 may be a p type semiconductorlayer including p type dopant. The p type semiconductor layer mayinclude the group III-V compound semiconductor materials selected fromthe group consisting of GaN, AlN, AlGaN, InGaN, InN, InAlGaN, AlInN,AlGaAs, GaP, GaAs, GaAsP and AlGaInP. The p type dopant may include Mg,Zn, Ga, Sr or Ba. The first conductive semiconductor layer 150 can beprepared as a single layer or a multi-layer, but the embodiment is notlimited thereto.

The first conductive semiconductor layer 150 supplies a plurality ofcarriers to the active layer 140.

The active layer 140 may include one of a single quantum well structure,a multiple quantum well (MQW) structure, a quantum wire structure and aquantum dot structure, but the embodiment is not limited thereto.

Electrons (or holes) injected through the second conductivesemiconductor layer 130 are recombined with holes (or electrons)injected through the first conductive semiconductor layer 150 at theactive layer 140, so that the active layer 140 emits the light based onthe band gap difference of the energy band determined according to theintrinsic material of the active layer 140.

If the active layer 140 has the quantum well structure, the active layer140 may have the single well structure or the multiple well structureincluding a well layer having the compositional formula ofIn_(x)Al_(y)Ga_(1-x-y)N (0≦x≦1, 0≦x+y≦1) and a barrier layer having thecompositional formula of In_(a)Al_(b)Ga_(1-a-b)N (0≦a≦1, 0≦b≦1,0≦a+b≦1). In addition, the well layer may include a material having anenergy band gap lower than that of the barrier layer.

The active layer 140 may have a stack structure of well/barrier layersby using the group III-V compound semiconductor materials. The groupIII-V compound semiconductor materials used for the active layer 140 mayinclude GaN, InGaN, or AlGaN. Therefore, for instance, the active layer140 may be prepared as a stack structure of InGaN well/GaN barrierlayers, InGaN well/AlGaN barrier layers, or InGaN well/InGaN barrierlayers, but the embodiment is not limited thereto.

Although not shown in the drawings, a conductive clad layer can beformed on and/or under the active layer 140. The conductive clad layermay include an AlGaN-based semiconductor. For instance, a p type cladlayer including p type dopant may be formed between the first conductivesemiconductor layer 150 and the active layer 140, and an n type cladlayer including n type dopant may be formed between the secondconductive semiconductor layer 130 and the active layer 140.

The conductive clad layer serves as a guide for preventing holes andelectrons injected into the active layer 140 from migrating to the firstand second conductive semiconductor layers 150 and 130. Thus, a largeramount of holes and electrons are recombined in the active layer 140 dueto the conductive clad layer, so that the light emitting efficiency ofthe light emitting device 100 can be improved.

The second conductive semiconductor layer 130 can be formed on theactive layer 140. The second conductive semiconductor layer 130 may bean n type semiconductor layer including n type dopant. The secondconductive semiconductor layer 130 may include the group III-V compoundsemiconductor materials selected from the group consisting of GaN, AlN,AlGaN, InGaN, InN, InAlGaN, AlInN, AlGaAs, GaP, GaAs, GaAsP and AlGaInP.The n type dopant may include Si, Ge, Sn, Se or Te. The secondconductive semiconductor layer 130 can be prepared as a single layer ora multiple layer, but the embodiment is not limited thereto.

A roughness or a concave-convex pattern 131 can be formed on the topsurface of the second conductive semiconductor layer 130 to improve thelight extraction efficiency. The roughness or the concave-convex pattern131 may be randomly formed through the wet etching or regularly formedthrough the patterning process, such as the photonic crystal structure,but the embodiment is not limited thereto.

The roughness or the concave-convex pattern 131 may have periodicpatterns. Concave patterns and convex patterns of the roughness or theconcave-convex pattern 131 may be rounded or formed with lateralsurfaces inclined at a predetermined angle to meet to each other at thevertex thereof.

For instance, the roughness or the concave-convex pattern 131 may havethe photonic crystal structure capable of selectively transmitting orreflecting the light having a specific wavelength. The roughness or theconcave-convex pattern 131 may have the period of 50 nm to 3000 nm, butthe embodiment is not limited thereto.

Meanwhile, a semiconductor layer having a polarity opposite to that ofthe first conductive semiconductor layer 150 may be formed under thefirst conductive semiconductor layer 150. If the first conductivesemiconductor layer 150 is a p type semiconductor layer, the secondconductive semiconductor layer 130 is an type semiconductor layer, orvice versa. Thus, the light emitting structure 145 may include at leastone of N—P junction, P—N junction, N—P—N junction and P—N—P junctionstructures.

The second conductive semiconductor layer 130 may include only the ntype semiconductor layer or may further include an undoped semiconductorlayer on the n type semiconductor layer, but the embodiment is notlimited thereto.

The undoped semiconductor layer is not doped with conductive dopant, sothe undoped semiconductor layer has electric conductivity remarkablylower than that of the n type semiconductor layer or the secondconductive semiconductor layer 130. The undoped semiconductor layer isgrown to improve crystalline property of the second conductivesemiconductor layer 130.

The doping concentration of the conductive dopant in the first andsecond conductive semiconductor layers 150 and 130 may be uniform ornon-uniform. That is, the light emitting structure 145 may have variousstructures, and the embodiment may not limit the structure of the lightemitting structure 145.

The second electrode 170 and the control switch 120 may be formed on thesecond conductive semiconductor layer 130.

The second electrode 170 can supply power to the light emittingstructure 100 together with the first electrode 160. For instance, thesecond electrode 170 can be prepared as a single layer or a multi-layerby using at least one selected from the group consisting of Ti, Cr, Ni,Al, Pt, Au, W, Cu, and Mo, but the embodiment is not limited thereto.The second electrode 170 may be formed through the deposition or platingprocess.

The control switch 120 is formed on the second conductive semiconductorlayer 130. Preferably, the control switch 120 is formed on an outerperipheral region of the second conductive semiconductor layer 150 tominimize absorption of the light emitted from the light emittingstructure 145.

The control switch 120 controls the on/off operation of the lightemitting device 100 according to the external control signal.

In detail, the on/off operation of the light emitting device 100 can becontrolled by the control switch 120 according to the external controlsignal, so the number of driver IC chips for driving the light emittingdevice 100 can be reduced and the on/off operation of the light emittingdevice 100 can be precisely controlled by using a simple wireinterconnection.

The control switch 120 can be formed on the top surface of the secondconductive semiconductor layer 130 of the light emitting structure 145through a simple process. The control switch 120 can be formed with afine size by doping silicon in the semiconductor manufacturing process,so the control switch 120 may not degrade the light emitting efficiencyof the light emitting device 100.

The control switch 120 may include a body 121 made from a siliconmaterial and doped with p type dopant, source and drain regions 122 and123 formed by implanting n type dopant onto an upper portion of the body121, a gate insulating layer 126 formed on the body 121 and the sourceand drain regions 122 and 123, a gate electrode 127 on the gateinsulating layer 126, a source electrode 124 on the source region 122,and a drain electrode 125 on the drain region 123.

In detail, the control switch 120 is a MOSFET switch, which controls theon/off operation and the brightness of the light emitting device 100according to the control signal applied to the gate electrode 127.

Although the control switch 120 according to the embodiment includes theMOSFET switch, the embodiment may not limit the type of the controlswitch 120. For instance, semiconductor switches, such as a JFET switch,a CMOS switch, or a BJT switch, can be used for the control switch 120.

The body 121 is made from a silicon material. In detail, the body 121can be simply formed by selectively removing a silicon substrate throughan etching process. That is, the body 121 of the control switch 120 canbe formed by selectively removing the silicon substrate used for growingand supporting the light emitting structure 145, so that themanufacturing process can be simplified and the process efficiency canbe improved.

The body 121 is doped with p type dopant, so the body 121 may form a ptype semiconductor. The p type dopant, for instance, may include atleast one of Mg, Be and B.

The source region 122 and the drain region 123 are formed on the body121. The source region 122 and the drain region 123 can be formed bydoping on an upper portion of the body 121 with n type dopant. The ntype dopant, for instance, may include at least one of N, P, As, or Sb.

In the meantime, if the first conductive semiconductor layer 150 is an ntype semiconductor layer and the second conductive semiconductor layer130 is an p type semiconductor layer, the n type dopant is implantedinto the body 121 and the p type dopant is implanted into the sourceregion 122 and the drain region 123.

The gate insulating layer 126 is formed on the top surfaces of the body121, the source region 122 and the drain region 123, and the gateelectrode 127 is formed on the gate insulating layer 126.

The control signal is applied to the gate electrode 127 and the gateinsulating layer 126 insulates the gate electrode 127 from the body 121,the source region 122 and the drain region 123.

For instance, the gate electrode 127 may include at least one selectedfrom the group consisting of Al, Cr, Ni, Ti, Cu, Pt, Ag, Pd, Rh and Au.In addition, the gate insulating layer 126 may include at least oneselected from the group consisting of SiO₂, HfO_(x), Al₂O₃, Si₃N₄ andTiO_(x).

The thickness of the gate insulating layer 126 can be controlled suchthat a channel can be formed between the source region 122 and the drainregion 123 as the control signal is applied to the gate electrode 127.The on/off operation of the light emitting device 100 is controlledaccording to the current flowing through the channel.

The source electrode 124 and the drain electrode 125 make contact withthe source region 122 and the drain region 123, respectively. Forinstance, the source electrode 124 and the drain electrode 125 mayinclude at least one selected from the group consisting of Al, Cr, Ni,Ti, Cu, Pt, Ag, Pd, Rh and Au.

In order to allow the control switch 120 to serve as a switch, one ofthe source electrode 124 and the drain electrode 125 is electricallyconnected to the second electrode 170 formed on the light emittingstructure 145 through a first wire 181 and the other of the sourceelectrode 124 and the drain electrode 125 is connected to the externalpower source through a second wire 182. In addition, another externalpower source can be connected to the gate electrode 127 through a thirdwire 183 to supply the control signal.

Hereinafter, the operation principle of the light emitting deviceaccording to the first embodiment will be described in detail. FIG. 3 isa circuit view showing the operational principle of the light emittingdevice according to the first embodiment.

Referring to FIG. 3, the control switch 120 is connected to the lightemitting structure 145 in series. The control switch 120 may include asemiconductor switch, such as a JFET switch, a CMOS switch, or a BJTswitch, which controls the light emitting structure 145 according to thecontrol signal G applied to the gate electrode 127.

The control signal G may be a high/low (or, on/off) control signal forsimply controlling the on/off operation of the light emitting device100, or a gray-scale control signal for controlling the brightness aswell as the on/off operation of the light emitting device 100, but theembodiment is not limited thereto.

If the control signal is the on/off control signal, the control switch120 is turned on by the on/off control signal, so that the supply of anegative voltage or a positive voltage to the second conductivesemiconductor layer 130 of the light emitting structure 145 by way ofthe source electrode 124, the channel layer, the drain electrode 125 andthe second electrode 170 can be controlled. Since the negative voltageor the positive voltage is supplied to the first electrode 160, thelight emitting structure 145 may emit the light based on the negativevoltage or the positive voltage supplied to the first and secondelectrodes 160 and 170.

If the control signal is the gray-scale control signal, the turn-on timeand the frequency of the turn-on operation of the control switch 120 arecontrolled by the gray-scale control signal. Thus, the light emittingstructure 145 emits the light in the form of a pulse to express the grayscale. The gray scale can be various expressed, and the embodiment isnot limited thereto.

Since the current flows through the channel formed between the sourceregion 122 and the drain region 123 of the control switch 120 as thecontrol signal G is applied to the control switch 120, the on/offoperation and/or the brightness of the light emitting device 100 can becontrolled.

For instance, if the control signal G is a high signal, the currentflows through the channel formed in the control switch 120, so that thecontrol switch 120 is turned on, and thus, the light emitting device 100is turned on. That is, the voltage is supplied to the light emittingstructure 145 so that the light emitting structure 145 can emit thelight. In contrast, if the control signal G is a low signal, the currentmay not flow through the channel formed in the control switch 120, sothat the control switch 120 is turned off, and thus, the light emittingdevice 100 is turned off. That is, the voltage is not supplied to thelight emitting structure 145.

As described above, since the control switch 120 is formed on the lightemitting structure 145 through the simple process with high efficiency,the on/off operation and/or the brightness of the light emitting device100 can be effectively controlled.

Hereinafter, the method of manufacturing the light emitting deviceaccording to the first embodiment will be described in detail.

FIGS. 4 to 12 are sectional views showing the method of manufacturingthe light emitting device according to the first embodiment.

Referring to FIG. 4, the light emitting structure 145 is formed on thesilicon substrate 110. The light emitting structure 145 can be formed bysequentially depositing the second conductive semiconductor layer 130,the active layer 140, and the first conductive semiconductor layer 150on the silicon substrate 110.

The silicon substrate 110 may include silicon. The silicon isinexpensive and easily processed as compared with a sapphire substrate.

The light emitting structure 145 can be formed on the silicon substrate110 through MOCVD (metal organic chemical vapor deposition), CVD(chemical vapor deposition), PECVD (plasma-enhanced chemical vapordeposition), MBE (molecular beam epitaxy), or HVPE (hydride vapor phaseepitaxy), but the embodiment is not limited thereto.

A buffer layer (not shown) can be formed between the second conductivesemiconductor layer 130 and the silicon substrate 110 to attenuate thelattice mismatch and difference of the thermal explanation coefficientbetween the second conductive semiconductor layer 130 and the siliconsubstrate 110. For instance, the buffer layer can be prepared as asingle layer or a multi-layer by using a semiconductor material havingthe compositional formula of In_(x)Al_(y)Ga_(1-x-y)N (0≦x≦1, 0≦x+y≦1).

Referring to FIG. 5, the protective member 155 may include a materialhaving electric insulating property or electric conductivity, lower thanthat of the light emitting structure 145. For instance, the protectivemember 155 may include at least one selected from the group consistingof SiO₂, Si_(x)O_(y), Si₃N₄, Si_(x)N_(y), SiO_(x)N_(y), Al₂O₃ and TiO₂.In this case, the protective member 155 may prevent the electric shortfrom occurring between the light emitting structure 145 and the firstelectrode 160, thereby improving the reliability of the light emittingdevice 100.

In addition, the protective member 155 may include a metal havingsuperior adhesive property. For instance, the protective member 155 mayinclude at least one selected from the group consisting of Ti, Ni, Pt,Pd, Rh, Ir and W. In this case, the protective member 155 may reinforcethe adhesive strength between the light emitting structure 145 and thereflective layer 157, so that the reliability of the light emittingdevice 100 can be improved. In addition, the protective member 155 maynot be broken or fragments of the protective member 155 may not begenerated when the laser scribing process or the laser lift off (LLO)process is performed to break a plurality of chips into individual chipunits, so that the reliability of the light emitting device 100 can beimproved. In addition, if the protective member 155 makes ohmic-contactwith the first conductive semiconductor layer 150, the current may flowthrough the protective member 155. In this case, the active layer 140,which overlaps on the protective member 155 in the vertical direction,can generate the light, so that the light emitting efficiency of thelight emitting device 100 may be further improved. For instance, if thefirst conductive semiconductor layer 150 is a p type semiconductorlayer, the protective member 155 may include a metallic material, suchas Ti, Ni or W, capable of forming the ohmic contact with respect to thep type semiconductor layer, but the embodiment is not limited thereto.

The protective member 155 can be formed through the deposition process,such as sputtering or PECVD, but the embodiment is not limited thereto.

Referring to FIG. 6, the ohmic contact layer 156 is formed on the lightemitting structure 145 and the reflective layer 157 is formed on theohmic contact layer 156. The ohmic contact layer 156 and the reflectivelayer 157 can be formed through the deposition process, such assputtering, PECVD, or E-beam evaporation.

The ohmic contact layer 156 may include at least one of ITO, Ni, Pt, Ir,Rh, and Ag. In addition, the reflective layer 157 may include a metal oran alloy including at least one of Ag, Al, Pt, Pd, and Cu.

Referring to FIG. 7, the adhesive layer 158 is formed on the reflectivelayer 157 and the protective member 155, and the first electrode 160 isformed on the adhesive layer 158. The first electrode 160 may includethe support member having conductivity.

The adhesive layer 158 may improve the interfacial adhesive strengthbetween the first electrode 160 and the light emitting structure 145.For instance, the adhesive layer 158 may include at least one selectedfrom the group consisting of Ti, Au, Sn, Ni, Cr, Ga, In, Bi, Cu, Ag andTa.

The first electrode 160 is prepared as a sheet and bonded onto the topsurface of the adhesive layer 158. Otherwise, the first electrode 160can be formed through the plating process or the deposition process. Inthis case, the adhesive layer 158 may be omitted.

For instance, the first electrode 160 may include at least one of Ti,Cr, Ni, Al, Pt, Au, W, Cu, Mo, and a semiconductor substrate doped withimpurities.

Referring to FIG. 8, the body 121 of the control switch 120 is formed byselectively removing the silicon substrate 110. Preferably, the body 120is formed on the outer peripheral region of the bottom surface of thelight emitting structure 145, but the embodiment is not limited thereto.

In detail, the silicon substrate 110 is selectively etched to form thebody 121. As shown in FIG. 8, the body 121 may have a polygonal columnshape, but the embodiment may not limit the shape and the manufacturingprocess for the body 121.

After that, the p type dopant is implanted into the body 121, so thatthe p type semiconductor layer is formed. The p type dopant may beimplanted into the silicon substrate 110 shown in FIG. 4 before thelight emitting structure 145 is formed. In other words, the p typedopant may be implanted into the silicon substrate 110 before the lightemitting structure 145 is formed or implanted into the body 121 afterthe body 121 has been formed.

Since the silicon substrate 110 can be easily removed through theetching process, the LLO (laser lift off) process, which may reduce theproduct yield of the light emitting device, can be omitted, so that thereliability of the manufacturing process for the light emitting device100 can be improved.

Meanwhile, the sapphire substrate can be employed as abase substrate ofthe light emitting structure 145 instead of the silicon substrate. Inthis case, the sapphire substrate is selectively removed through the LLOprocess and the body is formed 121 on the light emitting structure 145through the deposition process, but the embodiment is not limitedthereto.

Referring to FIG. 9, the n type dopant is selectively implanted into thelower portion of the body 121 to form the source region 122 and thedrain region 123.

In order to form the source region 122 and the drain region 123 indesired position, the mask pattern is formed in the body 121 and the ntype dopant is implanted along the mask pattern through the ionimplantation or the thermal diffusion, but the embodiment is not limitedthereto.

Referring to FIG. 10, the gate insulating layer 126 is formed such thatthe gate insulating layer 126 makes contact with the body 121, thesource region 122 and the drain region 123, and the gate electrode 127is formed on the gate insulating layer 126. In addition, the sourceelectrode 124 is formed on the source region and the drain electrode 125is formed on the drain region 123, thereby forming the control switch120.

For instance, the gate insulating layer 126 is deposited through CVD(chemical vapor deposition) or ALD (atomic layer deposition).

In addition, the gate electrode 127, the source electrode 124 and thedrain electrode 125 can be formed through the CVD, E-beam evaporation orsputtering, but the embodiment is not limited thereto.

Referring to FIG. 11, the isolation etching is performed with respect tothe light emitting structure 145 and the roughness or the concave-convexpattern 131 is formed on the top surface of the light emitting structure145, that is, on the top surface of the second conductive semiconductorlayer 130. In addition, the second electrode 170 is formed on the topsurface of the second conductive semiconductor layer 130, therebyproviding the light emitting device 100 according to the firstembodiment.

The light emitting device chips can be divided into individual chipunits through the isolation etching.

The lateral side of the light emitting structure 145 may be inclinedthrough the isolation etching.

In addition, the roughness or the concave-convex pattern 131 can beformed on the top surface of the light emitting structure 145, that is,on the top surface of the second conductive semiconductor layer 130through the isolation etching.

The isolation etching may include a dry etching, such as an ICP(inductively coupled plasma) etching.

The roughness or the concave-convex pattern 131 may be randomly formedthrough the wet etching or may have a photonic crystal structure alongthe mask pattern, but the embodiment is not limited thereto.

For instance, the second electrode 170 can be formed through the CVD,E-beam evaporation or sputtering.

Referring to FIG. 12, a wire interconnection is formed to allow thecontrol switch 120 to serve as a switch. Such a wire interconnection canbe formed after the light emitting device 100 has been mounted on thesubstrate, but the embodiment is not limited thereto.

For instance, as shown in FIG. 11, one of the source electrode 124 andthe drain electrode 125 is electrically connected to the secondelectrode 170 formed on the light emitting structure 145 through thefirst wire 181 and the other of the source electrode 124 and the drainelectrode 125 is connected to the external power source by a second wire182. In addition, another external power source can be connected to thegate electrode 127 through a third wire 183 to supply the controlsignal.

Hereinafter, the light emitting device and the method of manufacturingthe same according to the second embodiment will be described in detail.

FIG. 13 is a sectional view of the light emitting device according tothe second embodiment. The light emitting device 100B according to thesecond embodiment is similar to the light emitting device 100 accordingto the first embodiment except for the electrode structure. Thus,details of the elements and structures that have been previouslydescribed in the first embodiment will be omitted or simplified to avoidredundancy and the same reference numerals will be assigned to the sameelements.

Referring to FIG. 13, the light emitting device 100B according to thesecond embodiment includes a first electrode 160, an adhesive layer 158on the first electrode 160, a protective member 155 on the firstelectrode 160 or on an outer peripheral region of a top surface of theadhesive layer 158, a reflective layer 157 on the adhesive layer 158, anohmic contact layer 156 on the reflective layer 157, a light emittingstructure 145 on the protective member 155 and the ohmic contact layer156, a control switch 120 on the light emitting structure 145, and asecond electrode 171 formed on the control switch 120 and the lightemitting structure 145 to electrically connect the control switch 120 tothe light emitting structure 145.

The control switch 120 may include a body 121 made from a siliconmaterial and doped with p type dopant, source and drain regions 122 and123 formed by implanting n type dopant onto an upper portion of the body121, a gate insulating layer 126 formed on the body 121 and the sourceand drain regions 122 and 123, agate electrode 127 on the gateinsulating layer 126, and a source electrode 124 formed on one of thesource region 122 and the drain region 123.

The second electrode 171 is formed on the other of the source region 122and the drain region 123 and electrically connected to the lightemitting structure 145.

In this case, in order to prevent the second electrode 171 from beingelectrically connected to the body 121, an insulating layer 175 may beformed between the second electrode 171 and the lateral side of the body121.

If the second electrode 171 is electrically connected to the body 121,malfunction of the control switch 120 may occur.

The insulating layer 175 may be formed on a lateral side and a portionof the top surface of the body 121 and on a portion of the top surfaceof the second conductive semiconductor layer 130 adjacent to theconcave-convex pattern 131.

The insulating layer 175 may include at lest one selected from the groupconsisting of SiO₂, Si_(x)O_(y), Si₃N₄, Si_(x)N_(y), SiO_(x)N_(y), Al₂O₃and TiO₂.

The second electrode 171 can be electrically connected to one of thesource and drain regions 122 and 123 and the second conductivesemiconductor layer 130 of the light emitting structure.

The second electrode 171 electrically connected to the second conductivesemiconductor layer 130 may extend from the second conductivesemiconductor layer 130 so as to be electrically connected to one of thesource and drain regions 122 and 123.

The second electrode 171 is formed on the insulating layer 175. One endof the second electrode 171 is electrically connected to the secondconductive semiconductor layer 130 and the other end of the secondelectrode 171 is electrically connected to one of the source and drainregions 122 and 123.

The insulating layer 175 prevents the second electrode 171 from beingelectrically connected to the body 121 of the control switch 120, sothat the malfunction of the control switch 120 may not occur.

That is, different from the first embodiment, in which wires areadditionally provided to electrically connect one of the source anddrain regions 122 and 123 to the light emitting structure 145, the wirescan be omitted in the light emitting device 100B according to the secondembodiment by forming the second electrode 171. Thus, the light may notinterference with the wires.

FIG. 14 is a sectional view showing a light emitting device packageincluding the light emitting device according to the embodiments.

Referring to FIG. 14, the light emitting device package 30 includes apackage body 20, first to third lead electrodes 31 to 33 formed on thepackage body 20, the light emitting device 100 provided on the packagebody 20 to receive power from the first and second lead electrodes 31and 32 and the control signal from the third lead electrode 33, and amolding member 40 that surrounds the light emitting device 100.

The package body 20 may include silicon, synthetic resin or metallicmaterial. When viewed from the top, the package body 20 has a cavity 50formed with an inclined inner wall 53.

The first to third lead electrodes 31 to 33 are electrically isolatedfrom each other. For instance, the power is supplied to the first andthird lead electrodes 31 and 33 and the control signal is supplied tothe second electrode 32.

The first and second lead electrodes 31 and 32 may extend by passingthrough the package body 20. In detail, one ends of the first and secondlead electrodes 31 and 32 are disposed in the cavity 50 and the otherends of the first and second electrodes 31 and 32 are attached to anouter surface of the package body 20 and exposed to the outside.

The third lead electrode 33 is provided on the package body 20 betweenthe first and second lead electrodes 31 and 32.

The first to third lead electrodes 31 to 33 are coated with reflectivelayers to reflect the light emitted from the light emitting device 100,thereby improving the light efficiency. Further, the first to third leadelectrodes 31 to 33 dissipate heat generated from the light emittingdevice 100 to the outside.

The light emitting device 100 can be directly installed on the body 20or one of the first to third lead electrodes 31 to 33. For instance, thefirst electrode 160 (see, FIG. 1) of the light emitting device is formedon the third lead electrode 33, the first lead electrode 31 iselectrically connected to the source electrode 124 of the control switch120 by the second wire 182 (see, FIG. 1), and the second lead electrode32 is electrically connected to the gate electrode 127 of the controlswitch 120 by the third wire 183.

As described above, the drain electrode 125 of the control switch 120 iselectrically connected to the second electrode 170 by the firstelectrode 181.

The molding member 40 surrounds the light emitting device 100 to protectthe light emitting device 100. In addition, the molding member 40 mayinclude phosphors to change the wavelength of the light emitted from thelight emitting device 100.

The light emitting device or the light emitting device package accordingto the embodiment can be applied to the light unit. The light unitincludes a plurality of light emitting devices or a plurality of lightemitting device packages. The light unit may include the display deviceas shown in FIGS. 15 and 16 and the lighting device as shown in FIG. 17.In addition, the light unit may include a lighting lamp, a signal lamp,a headlight of a vehicle, and an electric signboard.

FIG. 15 is an exploded perspective view showing the display deviceaccording to the embodiment.

Referring to FIG. 15, the display device 1000 includes a light guideplate 1041, a light emitting module 1031 for supplying the light to thelight guide plate 1041, a reflective member 1022 provided below thelight guide plate 1041, an optical sheet 1051 provided above the lightguide plate 1041, a display panel 1061 provided above the optical sheet1051, and a bottom cover 1011 for receiving the light guide plate 1041,the light emitting module 1031, and the reflective member 1022. However,the embodiment is not limited to the above structure.

The bottom cover 1011, the reflective sheet 1022, the light guide plate1041 and the optical sheet 1051 may constitute a light unit 1050.

The light guide plate 1041 diffuses the light supplied from the lightemitting module 1031 to provide surface light. The light guide plate1041 may include transparent material. For instance, the light guideplate 1041 may include one of acryl-based resin, such as PMMA(polymethyl methacrylate, PET (polyethylene terephthalate), PC(polycarbonate), COC (cyclic olefin copolymer) and PEN (polyethylenenaphthalate) resin.

The light emitting module 1031 is disposed on at least one side of thelight guide plate 1041 to supply the light to at least one side of thelight guide plate 1041. The light emitting module 1031 serves as thelight source of the display device.

At least one light emitting module 1031 is provided to directly orindirectly supply the light from one side of the light guide plate 1041.The light emitting module 1031 may include a substrate 1033 and lightemitting device packages 30 according to the embodiments. The lightemitting device packages 30 are arranged on the substrate 1033 whilebeing spaced apart from each other at the predetermined interval. Thesubstrate 1033 may include a printed circuit board (PCB), but theembodiment is not limited thereto. In addition, the substrate 1033 mayalso include a metal core PCB (MCPCB) or a flexible PCB (FPCB), but theembodiment is not limited thereto. If the light emitting device packages30 are installed on the side of the bottom cover 1011 or on a heatdissipation plate, the substrate 1033 may be omitted. The heatdissipation plate partially makes contact with the top surface of thebottom cover 1011. Thus, the heat generated from the light emittingdevice packages 30 can be emitted to the bottom cover 1011 through theheat dissipation plate.

In addition, the light emitting device packages 30 are arranged suchthat light exit surfaces of the light emitting device packages 30 arespaced apart from the light guide plate 1041 by a predetermineddistance, but the embodiment is not limited thereto. The light emittingdevice packages 30 may directly or indirectly supply the light to alight incident surface, which is one side of the light guide plate 1041,but the embodiment is not limited thereto.

The reflective member 1022 is disposed below the light guide plate 1041.The reflective member 1022 reflects the light, which is travelleddownward through the bottom surface of the light guide plate 1041,toward the display panel 1061, thereby improving the brightness of thedisplay panel 1061. For instance, the reflective member 1022 may includePET, PC or PVC resin, but the embodiment is not limited thereto. Thereflective member 1022 may serve as the top surface of the bottom cover1011, but the embodiment is not limited thereto.

The bottom cover 1011 may receive the light guide plate 1041, the lightemitting module 1031, and the reflective member 1022 therein. To thisend, the bottom cover 1011 has a receiving section 1012 having a boxshape with an opened top surface, but the embodiment is not limitedthereto. The bottom cover 1011 can be coupled with the top cover (notshown), but the embodiment is not limited thereto.

The bottom cover 1011 can be manufactured through a press process or anextrusion process by using metallic material or resin, material. Inaddition, the bottom cover 1011 may include metal or non-metallicmaterial having superior thermal conductivity, but the embodiment is notlimited thereto.

The display panel 1061, for instance, is an LCD panel including firstand second transparent substrates, which are opposite to each other, anda liquid crystal layer interposed between the first and secondsubstrates. A polarizing plate can be attached to at least one surfaceof the display panel 1061, but the embodiment is not limited thereto.The display panel 1061 displays information by blocking the lightgenerated from the light emitting module 1031 or allowing the light topass therethrough. The display device 1000 can be applied to variousportable terminals, monitors of notebook computers, monitors or laptopcomputers, and televisions.

The optical sheet 1051 is disposed between the display panel 1061 andthe light guide plate 1041 and includes at least one transmittive sheet.For instance, the optical sheet 1051 includes at least one of adiffusion sheet, a horizontal and vertical prism sheet, and a brightnessenhanced sheet. The diffusion sheet diffuses the incident light, thehorizontal and vertical prism sheet concentrates the incident light ontothe display panel 1061, and the brightness enhanced sheet improves thebrightness by reusing the lost light. In addition, a protective sheetcan be provided on the display panel 1061, but the embodiment is notlimited thereto.

The light guide plate 1041 and the optical sheet 1051 can be provided inthe light path of the light emitting module 1031 as optical members, butthe embodiment is not limited thereto.

FIG. 16 is a sectional view showing a display device according to theembodiment.

Referring to FIG. 16, the display device 1100 includes a bottom cover1152, a substrate 1120 on which the light emitting device packages 30are arranged, an optical member 1154, and a display panel 1155.

The substrate 1120 and the light emitting device packages 30 mayconstitute the light emitting module 1060. In addition, the bottom cover1152, at least one light emitting module 1060, and the optical member1154 may constitute the light unit.

The bottom cover 1151 can be provided with a receiving section 1153, butthe embodiment is not limited thereto.

The optical member 1154 may include at least one of a lens, a lightguide plate, a diffusion sheet, a horizontal and vertical prism sheet,and a brightness enhanced sheet. The light guide plate may include PC orPMMA (Poly methyl methacrylate). The light guide plate can be omitted.The diffusion sheet diffuses the incident light, the horizontal andvertical prism sheet concentrates the incident light onto the displaypanel 1155, and the brightness enhanced sheet improves the brightness byreusing the lost light.

The optical member 1154 is disposed above the light emitting module 1060in order to convert the light emitted from the light emitting module1060 into the surface light. In addition, the optical member 1154 maydiffuse or collect the light.

FIG. 17 is a perspective view showing a lighting device according to theembodiment.

Referring to FIG. 17, the lighting device 1500 includes a case 1510, alight emitting module 1530 installed in the case 1510, and a connectionterminal 1520 installed in the case 1510 to receive power from anexternal power source.

Preferably, the case 1510 includes material having superior heatdissipation property. For instance, the case 1510 includes metallicmaterial or resin material.

The light emitting module 1530 may include a substrate 1532 and lightemitting device packages 30 installed on the substrate 1532. The lightemitting device packages 30 are spaced apart from each other or arrangedin the form of a matrix.

The substrate 1532 includes an insulating member printed with a circuitpattern. For instance, the substrate 1532 includes a PCB, an MCPCB, anFPCB, a ceramic PCB, and an FR-4 substrate.

In addition, the substrate 1532 may include material that effectivelyreflects the light. A coating layer can be formed on the surface of thesubstrate 1532. At this time, the coating layer has a white color or asilver color to effectively reflect the light.

At least one light emitting device package 30 is installed on thesubstrate 1532. Each light emitting device package 30 may include atleast one LED (light emitting diode) chip. The LED chip may include anLED that emits the light of visible ray band having red, green, blue orwhite color and a UV (ultraviolet) LED that emits UV light.

The light emitting device packages 30 of the light emitting module 1530can be variously combined to provide various colors and brightness. Forinstance, the white. LED, the red LED and the green LED can be combinedto achieve the high color rendering index (CRI).

The connection terminal 1520 is electrically connected to the lightemitting module 1530 to supply power to the light emitting module 1530.The connection terminal 1520 has a shape of a socket screw-coupled withthe external power source, but the embodiment is not limited thereto.For instance, the connection terminal 1520 can be prepared in the formof a pin inserted into the external power source or connected to theexternal power source through a wire.

Meanwhile, the method of manufacturing the light emitting deviceaccording to the embodiment includes the steps of forming the lightemitting structure by sequentially stacking the first conductivesemiconductor layer, the active layer and the second conductivesemiconductor layer on the silicon substrate; forming the conductivesupport member on the light emitting structure; selectively removing thesilicon substrate and implanting one of n type conductive dopant and ptype conductive dopant to form the body of the control switch; formingthe source and drain regions by implanting the other of the n typeconductive dopant and p type conductive dopant into the lower portion ofthe body; and forming the gate insulating layer Making contact with thebody and the source and drain regions and forming the gate electrodeunder the gate insulating layer.

According to the embodiment, the control switch can be formed on the topsurface of the light emitting structure through a simple process withhigh efficiency, so that the on/off operation and/or the brightness ofthe light emitting device can be effectively controlled.

According to the embodiment, the light emitting device includes thecontrol switch, so an additional component is not necessary to connect aswitch to the light emitting device to control the operation of thelight emitting device.

According to the embodiment, the light emitting device including thecontrol switch having the simple structure can be manufactured throughthe simple process, so that the light emitting device is applicable invarious fields.

According to the embodiment, the control switch is provided in the lightemitting device, so that the electric disconnection between the switchcomponents and the light emitting device can be prevented.

Any reference in this specification to “one embodiment,” “anembodiment,” “example embodiment,” etc., means that a particularfeature, structure, or characteristic described in connection with theembodiment is included in at least one embodiment of the invention. Theappearances of such phrases in various places in the specification arenot necessarily all referring to the same embodiment. Further, when aparticular feature, structure, or characteristic is described inconnection with any embodiment, it is submitted that it is within thepurview of one skilled in the art to effect such feature, structure, orcharacteristic in connection with other ones of the embodiments.

Although embodiments have been described with reference to a number ofillustrative embodiments thereof, it should be understood that numerousother modifications and embodiments can be devised by those skilled inthe art that will fall within the spirit and scope of the principles ofthis disclosure. More particularly, various variations and modificationsare possible in the component parts and/or arrangements of the subjectcombination arrangement within the scope of the disclosure, the drawingsand the appended claims. In addition to variations and modifications inthe component parts and/or arrangements, alternative uses will also beapparent to those skilled in the art.

What is claimed is:
 1. A light emitting device, comprising: a firstelectrode; a light emitting structure including a first semiconductorlayer, an active layer and a second semiconductor layer on the firstelectrode; a second electrode on the light emitting structure; a controlswitch on the light emitting structure, wherein the control switchincludes a body including a first dopant, and source and drain regionsincluding a second dopant on the body, and wherein the second electrodeextends to one of the source and drain regions from a portion of thesecond semiconductor layer via a lateral side of the body.
 2. The lightemitting device of claim 1, further comprising an insulating layerbetween the second electrode and the body.
 3. The light emitting deviceof claim 1, wherein the control switch further comprises a gateinsulating layer on the body between the source and drain regions and agate electrode on the gate insulating layer.
 4. The light emittingdevice of claim 1, wherein the body of the control switch is disposed ona top surface of the second semiconductor layer.
 5. The light emittingdevice of claim 1, wherein the body of the control switch is directlydisposed on a top surface of the second semiconductor layer.
 6. Thelight emitting device of claim 1, wherein the first electrode isdisposed on a bottom surface of the first semiconductor layer.
 7. Thelight emitting device of claim 1, wherein both of the body and thesecond electrode are directly disposed on a top surface of the secondsemiconductor layer.
 8. The light emitting device of claim 1, whereinthe control switch includes a semiconductor switch.
 9. The lightemitting device of claim 1, wherein the control switch is disposed at anouter peripheral region of the light emitting structure.
 10. The lightemitting device of claim 1, wherein the body includes silicon.
 11. Alight emitting device, comprising: a first electrode; a light emittingstructure including a first semiconductor layer on the first electrode,an active layer on the first semiconductor layer and a secondsemiconductor layer on the active layer; a second electrode on thesecond semiconductor layer; a body on the second semiconductor layer;source and drain regions on the body; a gate insulating layer on thebody between the source and drain regions; and a gate electrode on thegate insulating layer, an insulating layer between the second electrodeand the body, wherein the second electrode is electrically connected toone of the source region or the drain region.
 12. The light emittingdevice of claim 11, wherein the second electrode extends to one of thesource and drain regions from a portion of the second semiconductorlayer via a lateral side of the body.
 13. The light emitting device ofclaim 11, wherein the body is directly disposed on a top surface of thesecond semiconductor layer.
 14. The light emitting device of claim 11,further comprising at least one of a reflective layer or an ohmiccontact layer between the first electrode and the light emittingstructure.
 15. The light emitting device of claim 11, further comprisinga protective member on an outer peripheral region of a top surface ofthe first electrode, and wherein the protective member verticallyoverlaps with at least one portion of the body of the control switch.16. A light emitting device, comprising: a first electrode; a lightemitting structure including a first semiconductor layer on the firstelectrode, an active layer on the first semiconductor layer and a secondsemiconductor layer on the active layer; a second electrode on thesecond semiconductor layer; a body on the second semiconductor layer;source and drain regions on the body; a gate insulating layer on thebody between the source and drain regions; a gate electrode on the gateinsulating layer, and a protective member on an outer peripheral regionof a top surface of the first electrode, wherein the second electrodeextends to one of the source and drain regions from a portion of thesecond semiconductor layer via a lateral side of the body.
 17. The lightemitting device of claim 16, further comprising an insulating layerbetween the second electrode and the body.
 18. The light emitting deviceof claim 16, wherein the second electrode is electrically connected toone of the source region or the drain region, and
 19. The light emittingdevice of claim 16, wherein the body is directly disposed on a topsurface of the second semiconductor layer.
 20. The light emitting deviceof claim 16, wherein the protective member vertically overlaps at leasta portion of the body of the control switch.